Workaround for glibc semaphore bug.

src/heap/mark-compact.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_MARK_COMPACT_H_
 #define V8_HEAP_MARK_COMPACT_H_
 
 #include <deque>
 
 #include "src/base/bits.h"
@@ skipping 626 matching lines @@
 
   explicit MarkCompactCollector(Heap* heap);
 
   bool WillBeDeoptimized(Code* code);
   void ClearInvalidRememberedSetSlots();
 
   void ComputeEvacuationHeuristics(int area_size,
                                    int* target_fragmentation_percent,
                                    int* max_evacuated_bytes);
 
-#ifdef DEBUG

[ulan, 2016/05/20 11:28:24]

I moved this down.

-  enum CollectorState {
-    IDLE,
-    PREPARE_GC,
-    MARK_LIVE_OBJECTS,
-    SWEEP_SPACES,
-    ENCODE_FORWARDING_ADDRESSES,
-    UPDATE_POINTERS,
-    RELOCATE_OBJECTS
-  };
-
-  // The current stage of the collector.
-  CollectorState state_;
-#endif
-
-  MarkingParity marking_parity_;
-
-  bool was_marked_incrementally_;
-
-  bool evacuation_;
-
   // Finishes GC, performs heap verification if enabled.
   void Finish();
 
   // -----------------------------------------------------------------------
   // Phase 1: Marking live objects.
   //
   //  Before: The heap has been prepared for garbage collection by
   //          MarkCompactCollector::Prepare() and is otherwise in its
   //          normal state.
   //
@@ skipping 165 matching lines @@
 
 #ifdef DEBUG
   friend class MarkObjectVisitor;
   static void VisitObject(HeapObject* obj);
 
   friend class UnmarkObjectVisitor;
   static void UnmarkObject(HeapObject* obj);
 #endif
 
   Heap* heap_;
+
+  base::Semaphore page_parallel_job_semaphore_;
+
+#ifdef DEBUG
+  enum CollectorState {
+    IDLE,
+    PREPARE_GC,
+    MARK_LIVE_OBJECTS,
+    SWEEP_SPACES,
+    ENCODE_FORWARDING_ADDRESSES,
+    UPDATE_POINTERS,
+    RELOCATE_OBJECTS
+  };
+
+  // The current stage of the collector.
+  CollectorState state_;
+#endif
+
+  MarkingParity marking_parity_;
+
+  bool was_marked_incrementally_;
+
+  bool evacuation_;
+
+  // True if we are collecting slots to perform evacuation from evacuation
+  // candidates.
+  bool compacting_;
+
+  bool black_allocation_;
+
+  bool have_code_to_deoptimize_;
+
   base::VirtualMemory* marking_deque_memory_;
   size_t marking_deque_memory_committed_;
   MarkingDeque marking_deque_;
   std::vector<std::pair<void*, void*>> wrappers_to_trace_;
 
   CodeFlusher* code_flusher_;
 
   EmbedderHeapTracer* embedder_heap_tracer_;
 
-  bool have_code_to_deoptimize_;
-
   List<Page*> evacuation_candidates_;
   List<Page*> newspace_evacuation_candidates_;
 
-  // True if we are collecting slots to perform evacuation from evacuation
-  // candidates.
-  bool compacting_;
-
-  bool black_allocation_;
-
   Sweeper sweeper_;
 
   friend class Heap;
   friend class StoreBuffer;
 };
 
 
 class EvacuationScope BASE_EMBEDDED {
  public:
   explicit EvacuationScope(MarkCompactCollector* collector)
       : collector_(collector) {
     collector_->set_evacuation(true);
   }
 
   ~EvacuationScope() { collector_->set_evacuation(false); }
 
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_MARK_COMPACT_H_